The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it may be described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present technology.
The engine cooling system of a typical internal combustion engine pumps coolant through the engine body and head where it picks up the heat and eventually rejects the heat via the radiation mounted on the front of the car. A thermostat controls the temperature of the coolant for safe operation.
During engine operation, typically 53% of combustion energy is transferred as heat to the cylinder walls. The energy transferred to the cylinder walls causes the coolant, the metallic structure (including the block and crankshaft) and the lubricant to warm up. However, less than half of this heat is found to warm-up any of the ancillary circuits (such as the lubricant or coolant), while the majority is instead lost directly to the environment (termed ‘unused heat’).
It is widely recognized among car manufacturers that a 100 second quicker warm-up produces a reduction of 1% in fuel consumption and, consequently, in CO2 emission for a small-medium weight car. Additionally, at sub-zero temperatures the heat loss from the engine walls is quite significant, resulting in an even greater compromise of fuel efficiency under these conditions. Thus, if a greater proportion of unused heat could be captured and directed toward engine heating, fuel efficiency would improve and CO2 emission would decrease after a cold start.